Refocusable lens system with mutually-applanating internal surfaces

ABSTRACT

An accommodating (re-focusable) lens system a body of which includes, upon being assembled, first and second individual lenslets having first and second optical portions sequentially disposed along an optical axis. Change in optical-power accommodation of the system is achieved by changing an applanated area of contact between the lenslets in response to force applied to the lenslets and transformed into an axial force. In specific case, the first and second lenslets form an intraocular lens (IOL) and have respective haptic portions, interlocked as a result of rotating of one lenslet with respect to another such as to bring first and second lenslets in contact at an axial point. The applanated area of contact is changed, then, in response to a radially-directed force caused by a change of distance between the interlocked ends of the haptics and transferred to the optical portions through the interlocked haptics. When installed in a natural lens capsule after the cataract extraction, the optical power of such IOL is gradually modifiable due to a change of curvature of the capsule caused by operation of a ciliary muscle.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of pending InternationalPatent Application No. PC/US2014/050318 filed on Aug. 7, 2014, whichdesignates the United States and claims priority from and benefit of theU.S. Provisional Patent Applications No. 61/949,268 filed on Mar. 7,2014 and of the U.S. patent application Ser. No. 14/334,514 filed onJul. 17, 2014. The disclosure of each of the above-mentioned patentdocuments is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to refocusable lens systems and, inparticular, to lens systems having first and second aspherical surfacesthat flatten each other in operation thereby continuously altering theeffective focal length of the system. Such lens systems can be used inophthalmological instruments (for example, as intraocular lenses) oropto-mechanical instruments employing a variable-focus lens.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood by referring to thefollowing Detailed Description in conjunction with the generallynot-to-scale Drawings, of which:

FIG. 1A is a diagram schematically showing, in side view, an embodimentof the anterior lens component of an embodiment of the invention;

FIG. 1B is a diagram schematically showing, in side view, an embodimentof the posterior lens component of an embodiment of the invention;

FIG. 2A is a diagram schematically illustrating a front view of an IOLaccording to one embodiment of the present invention, with haptics ofthe anterior and posterior lens components of FIGS. 1A, 1B interlocked;

FIG. 2B a diagram schematically illustrating the embodiment of FIG. 2Ain side view;

FIG. 3 schematically shows, in front view, a posterior lens component ofFIG. 1B. Haptics of the posterior lens are shaped to include arcedlocking notches and interlocking grooves forming a portion of mechanismof interlocking between the anterior and posterior lens components. In aspecific embodiment, an arced interlocking groove is substantiallytangentially parallel to a perimeter of an optical portion of theassociated lens;

FIG. 4 is a diagram illustrating an example of operable placement of theembodiment of FIGS. 2A, 2B in a capsule membrane of an eye in place of anatural eye lens;

FIGS. 5A, 5B schematically illustrate mutually-imposed deformation of aposterior surface of the anterior lens and an anterior surface of theposterior lens, of the embodiment of FIGS. 2A and 2B, causing a changeof accommodating distance as a result of force transferred to theinterlocked haptics of the IOL from ciliary muscle. FIG. 5A:accommodation at a near-distance point; FIG. 5B: accommodation at afar-away point;

FIG. 6 schematically shows an enlarged central portion of the embodimentof FIG. 5B, illustrating the mutually-imposed flattening of thecontacting surfaces of the embodiment that accompanies the accommodationof the IOL at a long distance;

FIGS. 7A, 7B illustrate layouts of a model of the human eye with thepseudophakic lens of the invention placed therein in Zemax® opticalmodeling software, showing the shape change of the front and backsurface of the lens to alter the eye's focal distance from infinity tonear;

FIGS. 8A, 8B present spot diagrams generated in Zemax® andcorresponding, respectively, to layouts of FIGS. 7A, 7B;

FIGS. 9A, 9B show images of the same object formed with an embodiment ofthe invention accommodated according to the layouts of FIGS. 7A, 7B;

FIG. 10 is a diagram of a human eye;

FIG. 11 is a flow-chart schematically depicting a method according to anembodiment of the invention;

FIG. 12 is a plot showing a dependence of a degree of surfaceapplanation of an embodiment of FIGS. 7A, 7B as a function of forcetransferred to the surface;

FIG. 13 is a schematic diagram of a related embodiment of the invention;

FIGS. 14A and 14B are diagrams illustrating in side and front views anembodiment of a variable-focus lens system when no applanation is causedby mutually-facing internal surfaces of the system;

FIGS. 15A and 15B illustrate the side and front views of the embodimentof FIGS. 14, 14B after the array of individual lenses of the embodimenthas been axially compressed;

FIGS. 16A and 16B are diagrams illustrating, in side and front views, anembodiment of a variable-focus lens system including anterior sub-systemand posterior subsystem the focal lengths of which are individuallyadjustable according to the embodiment of the invention;

FIG. 17 is a flow-chart schematically depicting a method according to anembodiment of the invention.

SUMMARY

Embodiments of the invention provide a pseudophakic lens assembly thatcontains a first lenslet having a first optical power and a firstrotationally-symmetric optical portion defining a clear aperture of thefirst lenslet and a second lenslet having a second optical power and asecond rotationally-symmetric optical portion defining a clear apertureof the second lenslet. The first lenslet includes at least two firsthaptic portions, each having a proximal end integrated with a peripheralregion of the first optical portion and a distal free end. The secondlenslet includes at least two second haptic portions respectivelycorresponding to the at least two first haptic portions, such that eachof the at least two second haptic portions includes a notch and agroove. The groove is dimensioned to accommodate a corresponding distalfree end therein when the first and second lenslets are coaxiallypositioned to define an axial point of contact between mutually-facingsurfaces thereof such that each of the at least two first hapticportions is interlocked with the respectively corresponding of the atleast two second haptic portions through the notch. The embodiment ofthe pseudophakic lens assembly is configured such as to increase an areaof contact between the mutually-facing surfaces in response to aradially-vectored force transferred to the first and secondrotationally-symmetric optical portions through the at least two firstand second interlocked haptic portions. In particular, the lens assemblycan be configured such as to have an area of contact between themutually-facing surfaces reduced in response to a radially-vectoredforce transferred to the first and second rotationally-symmetric opticalportions through the at least two first and second interlocked hapticportions. Alternatively or in addition, the lens assembly is configuredsuch as to have a portion of each of the mutually-facing surfacesapplanated around an optical axis of the assembly in response to aradially-vectored force transferred to the first and secondrotationally-symmetric optical portions through the at least two firstand second interlocked haptic portions, thereby reducing the opticalpower of the assembly. In a specific embodiment, at least one of themutually-facing surfaces in an unstressed state includes a prolateaspheric surface. In a related embodiment, a first haptic portion isinterlocked with a second haptic portion as a result of a relativerotation of at least one of the first and second lenslets about anoptical axis. An embodiment of the assembly may be configured to reduceat least one of the first and second optical powers in response toincreasing a distance between free distal ends of the at least two firsthaptic portions that have been interlocked with the respectivelycorresponding of at least two second haptic portions.

In one specific embodiment, a pseudophakic lens assembly additionallyincludes a third lenslet having a third optical power and a thirdrotationally-symmetric optical portion defining a clear aperture of thethird lenslet and at least two third haptic portions. The at least twothird haptic portions are, in operation of the lens, interlocked with atleast one of (i) the at least two first haptic portions and (ii) the atleast two second haptic portions such as to define a point of contactbetween a first surface of the at least one of the first and secondlenslets and a second surface of the third lenslet, wherein the firstand second surfaces being are facing each other. The assembly isconfigured such that an area of contact between the first and secondsurfaces is changed in response to a radially-vectored force transferredto rotationally-symmetric portions of the assembly through interlockedhaptic portions. Optionally, this specific embodiment is configured suchas to have a portion of at least one of the first and second surfacesurfaces applanated around an optical axis of the assembly, in responseto the radially-vectored force.

Embodiments of the invention further provide a method for operating apseudophakic lens assembly. Such method includes juxtaposing first andsecond lenslets coaxially such that a surface of the first lenslet and asurface of the second lenslet face each other. These lenslets areconfigured such that the first lenslet includes at least two firsthaptic portions, each having a proximal end integrated with a peripheralregion of the first optical portion and a distal end; and the secondlenslet includes at least two second haptic portions respectivelycorresponding to the at least two first haptic portions. The methodfurther includes interlocking each of these at least two first hapticportions with the respectively corresponding at least two secondportions by rotating at least one of the first and second lenslets withrespect to another about an axis such as (i) to form the lens assembly,in which the first and second lenslets are securely affixed to oneanother and (ii) to define an axial point of contact between said facingeach other surfaces of the first and second lenslets. The method furtherincludes varying an area of contact between the facing each othersurfaces of the first and second lenslets in response to aradially-vectored force transferred to optical the first and secondoptical portions through the at least two first and second hapticportions interlocked with one another.

An embodiment of the method may additionally include applanating atleast a portion of at least one of the facing each other surfaces of thefirst and second lenslets within the area of contact, and increasing thearea of contact by increasing a distance between distal ends of the atleast two first haptic portions. (In a specific embodiment, when onlytwo lenslets are being juxtaposed, each lenslet may have a prolateaspheric surface in an unstressed state, and the step of varyingincludes causing prolate aspheric surfaces of the two lenslets to applyforce towards one another such as to mutually applanate each other.)Alternatively or in addition, the method may contain a step of insertingthe first and second lenslets individually into an eye through anincision in a cornea; and conforming a curvature of a posterior surfaceof the lens assembly to an internal surface of a natural lens capsule ofthe eye. In this specific case, the steps of juxtaposing andinterlocking may be carried out after the step of inserting. In arelated embodiment, the may additionally include changing an opticalpower of said pseudophakic lens assembly by causing the facing eachother surfaces of the first and second lenslets to mutually deform eachother. The step of changing an optical power may include changing acurvature of an axial portion of at least one of the facing each othersurfaces of the first and second lenslets by a first amount whilechanging a curvature of an annular portion of said at least one of thefacing each other surfaces by a second amount that is smaller than thefirst amount, where the annular portion circumscribes the axial portion.The step of interlocking may include affixing a first haptic portion ina notch of the second haptic portion and a corresponding distal end ofthe first haptic portion in a groove of the second haptic portion, saidgroove being substantially tangentially parallel to a perimeter of thefirst optical portion.

In a specific implementation, the method may additionally include thesteps of (i) juxtaposing a third lenslet (having at least two thirdhaptic portions) coaxially with said first and second lenslets, (ii)interlocking each of said at least two third haptic portions with atleast one of respectively corresponding at least two first hapticportions, and respectively corresponding at least two second hapticportions. The interlocking is achieved by rotating at least one of saidfirst, second, and third lenslets about an axis such as (a) to form asecond lens assembly, in which the first, second, and third lenslets aresecurely affixed to one another and (b) to define a point of contactbetween first and second facing each other immediately adjacentsurfaces, the first surface being a surface of the third lenslet and asecond surface being a surface of at least one of the first and secondlenslets. The specific implementation of the method may be complementedby a step of varying a second area of contact between said first andsecond surfaces in response to the radially-vectored force, whichvarying may optionally include causing at least one of the first andsecond surfaces to apply force towards one another such as to applanateat least one of the first and second surfaces.

Embodiments additionally provide a variable-focal-length lens systemthat includes (i) a first lenslet having a first optical power and afirst rotationally-symmetric optical portion defining a clear apertureof the first lenslet, and (ii) a second lenslet having a second opticalpower and a second rotationally-symmetric optical portion defining aclear aperture of the second lenslet, such that the first and secondlenslets are disposed co-axially to define a contact between surfacesthereof at an axial point. The system additionally includes means fortransfer of motion applied to a surface of at least one of the first andsecond lenslets to a force applanating at least one of said surfacesabout the axial point such that an area of applanation of the surface inquestion depends on a degree of such motion. The system may be equippedwith a housing unit enclosing the first and second lenslets andmechanically cooperated with the means of transfer of motion which, in aspecific case, may include a piston movable internally with respect tothe housing. In one embodiment, the lens system is configured to have afirst surface of the first lenslet and a second surface of the secondlenslet interact with one another, in response to a non-zero forcetransferred to at least one of the first and second surfaces by saidmeans, such as to mutually applanate one another to define respectiveapplanated areas diameters of which progressively increase with increasein such non-zero force created by means for transfer of motion. In aspecific case, a process of increase in a diameter of an applanated areaof any of the first and second surfaces response to increase of suchforce, optical aberrations of the lens system that are caused by changesin the diameter of the applanated area are minimized.

DETAILED DESCRIPTION

Needs for a variable-focus lens system are numerous and range from usesin optical engineering (such as, for example, in a photocamera) to usesin medicine (for example, as an ophthalmological element). While theidea of the present invention was facilitated by the ophthalmologicaluse of a variable-focus lens, the following disclosure additionallypresents related embodiments the application of which goes beyondophthalomolgy.

To this end, references throughout this specification to “oneembodiment,” “an embodiment,” “a related embodiment,” or similarlanguage mean that a particular feature, structure, or characteristicdescribed in connection with the referred to “embodiment” is included inat least one embodiment of the present invention. Thus, appearances ofthe phrases “in one embodiment,” “in an embodiment,” and similarlanguage throughout this specification may, but do not necessarily, allrefer to the same embodiment. It is to be understood that no portion ofdisclosure, taken on its own and in possible connection with a figure,is intended to provide a complete description of all features of theinvention.

In addition, it is to be understood that no single drawing is intendedor even capable to support a complete description of all features of theinvention. In other words, a given drawing is generally descriptive ofonly some, and generally not all, features of the invention. A givendrawing and an associated portion of the disclosure containing adescription referencing such drawing do not, generally, contain allelements of a particular view or all features that can be presented isthis view, for purposes of simplifying the given drawing and discussion,and to direct the discussion to particular elements that are featured inthis drawing. A skilled artisan will recognize that the invention maypossibly be practiced without one or more of the specific features,elements, components, structures, details, or characteristics, or withthe use of other methods, components, materials, and so forth.Therefore, although a particular detail of an embodiment of theinvention may not be necessarily shown in each and every drawingdescribing such embodiment, the presence of this detail in the drawingmay be implied unless the context of the description requires otherwise.In other instances, well known structures, details, materials, oroperations may be not shown in a given drawing or described in detail toavoid obscuring aspects of an embodiment of the invention that are beingdiscussed. Furthermore, the described single features, structures, orcharacteristics of the invention may be combined in any suitable mannerin one or more further embodiments.

The invention as recited in claims appended to this disclosure isintended to be assessed in light of the disclosure as a whole.

One common need of a variable-focus lens arises as a result of theclouding of the natural lens of an eye, which is often age-related,referred to as cataract. Visual loss, caused by the cataract, occursbecause opacification of the lens obstructs light from traversing thelens and being properly focused on to the retina. The cataract causesprogressive decreased vision along with a progressive decrease in theindividual's ability to function in his daily activities. This decreasein function with time can become quite severe, and may lead toblindness. The cataract is the most common cause of blindness worldwideand is conventionally treated with cataract surgery, which has been themost common type of surgery in the United States for more than 30 yearsand the frequency of use of which is increasing. As a result of cataractsurgery, the opacified, clouded natural crystalline lens of an eye isremoved and replaced with a synthetic and clear, optically transparentsubstitute lens (often referred to as an intraocular lens or IOL) torestore the vision.

The use of such customized synthetic IOLs that are properly sized for agiven individual—often referred to as intraocular lenses—has been provenvery successful at restoring vision for a predetermined, fixed focaldistance. The most common type of IOL for cataract treatment is known aspseudophakic IOL that is used to replace the clouded over crystallinelens. (Another type of IOL, more commonly known as a phakic intraocularlens (PIOL), is a lens which is placed over the existing natural lensused in refractive surgery to change the eye's optical power as atreatment for myopia or nearsightedness.) An IOL usually includes of asmall plastic lens with plastic side struts (referred to as “haptics”),which hold the IOL in place within the capsular bag inside the eye. IOLswere traditionally made of an inflexible material (such as PMMA, forexample), although this is being superseded by the use of flexiblematerials. Such lenses, however, are not adapted to restore the eye'sability to accommodate, as most IOLs fitted to an individual patienttoday are monofocal lenses (lenses with a fixed, single position of afocal point) that are matched to “distance vision”.

Accommodation is the eye's natural ability to change the shape of itslens and thereby change the lens' focal distance. The accommodation ofthe eye allows an individual to focus on an object at any given distancewithin the field-of-view (FOV) with a feedback response of an autonomicnervous system. Accommodation of an eye occurs unconsciously, withoutthinking, by innervating a ciliary body muscle in the eye. The ciliarymuscle adjusts radial tension on the natural lens and changes the lens'curvature which, in turn, adjusts the focal distance of the eye's lens.

Without the ability to accommodate one's eye, a person has to rely onauxiliary, external lenses (such as those used in reading glasses, forexample) to focus his vision on desired objects. Typically, cataractsurgery will leave an individual with a substantially fixed focaldistance, usually greater than 20 feet. This allows the individual toparticipate in critical activities, such as driving, without usingglasses. For activities such as computer work or reading (which requireaccommodation of eye(s) at much shorter distance), the individual thenneeds a separate pair of glasses.

Several attempts have been made to restore eye accommodation ascorollary to cataract surgery. Some of contemporary IOL designs attemptto exploit the optical effect of anterior lens displacement thatproduces myopic shift and thus improve near vision; early clinicalevaluation confirmed some degree of accommodative effect that isproportional to the measured displacement of the optic.

The most successful of used methodologies relies on using a substitutelens that has two or three discrete focal lengths to provide a patientwith limited visual accommodation in that optimized viewing is providedat discrete distances—optionally, both for distance vision and nearvision. Such IOLs are sometimes referred to as a “multifocal IOLs”. Thepractical result of using such IOLs has been fair, but the designcompromises the overall quality of vision. Indeed, such multifocal IOLsuse a biconvex lens combined with a Fresnel prism to create two or morediscreet focal distances. The focal distance to be utilized is in focuswhile there is a superimposed defocused image from the other focaldistances inherent in the lens. Also, the Fresnel prism contains aseries of imperfect dielectric boundary-related discontinuities, whichcreate scatter perceived as glare by the patient. Some patients reportglare and halos at night time with these lenses.

Another methodology may employ altering the position of afixed-focal-length substitute lens (often referred to as an“accommodating IOL”) with contraction of a ciliary muscle to achieve achange in the working distance of the eye. These “accommodating IOLs”interact with ciliary muscles and zonules, using hinges at both ends to“latch on” and move forward and backward inside the eye using the samenatural accommodation mechanism. In other words, while the fixed focallength of such IOL does not change in operation, the focal point of an“accommodating IOL” is repositioned (due to a back-and-forth movement ofthe IOL itself) thereby changing the working distance between the retinaand the IOL and, effectively, changing the working distance of the IOL.Such IOL typically has an approximately 4.5-mm square-edged opticalportion and a long hinged plate design with polyimide loops at the endof the haptics. The hinges are made of an advanced silicone (such asBioSil). While “accommodating IOLs” have the potential to eliminate orreduce the dependence on glasses after cataract surgery and, for some,may be a better alternative to refractive lens exchange (RLE) andmonovision, this design has diminished in popularity due to poorperformance and dynamic range of movement that is not sufficient forproper physiological performance of the eye.

Another shortcoming of the use of most currently existing structures ofaccommodating lenses is known to be inability to perform a lasercapsulotomy procedure (to remove a film growth over the ventralposterior surface of the lens capsule, which degrades the vision, as aresult of which the spatial continuity of the capsule across the wholeposterior surface of the IOL lens may become uncertain.

Therefore, there remains an unresolved need in an IOL that is structuredto be, in operation, continuously accommodating, with gradually,non-discretely and/or monotonically adjustable focal length.

According to an embodiment of the invention, the problem ofaccommodating the focal length of an IOL is solved by forming the IOL asa coaxial assembly of at least two individualinterlocked-through-the-haptics lenslets and utilizing a force mechanismsupplied by the eye's ciliary muscle to vary an area of contact offacing each other surfaces of such lenslets and to applanate thesesurfaces within the area of contact. The individual lenslets of the IOLassembly are provided with at least one flexible prolate asphericalsurface the curvature of which and is juxtaposed in such spatialrelation with respect to the ciliary muscle that force, transferred tothe optical portion of the IOL through the interlocked haptics by themuscle, applies pressure on the facing each other surfaces of theimmediately adjacent individual lenslets to change the curvatures ofsuch surfaces in the area of contact and, thereby, the optical power ofthe overall IOL as well. Such variation of the focal length is achievedwithout substantial repositioning of the IOL itself.

According to a related embodiment of the invention, the problem ofvarying the focal length of a multi-lens optical system is solved byproviding a co-axially queued individual lenses, at least two of whichare in contact at a point located at the axis, and utilizing a means foraxially compressing at least a portion of this array of lenses such thatlens surfaces that are in contact at the axial point deform each otherin response to the axially-applied pressure (and, optionally, inresponse to minute axial movement of a component of the system) toincrease an area, of each surface, that is applanated. The applanationof the mutually-deforming internal surfaces of the lens system isreversible in response to reverse operation of means for axialcompression that causes the reduction of force with which one of thecontacting-each-other surfaces interacts with another.

Numbering of Structural Surfaces.

In describing the order of elements or components in an embodiment of alens system of the invention or a sub-set of such system, the followingconvention will be generally followed herein, unless stated otherwise.The order in which the surfaces of sequentially positioned structuralelements of the lens assembly are viewed along a direction of lightincident on the lens system, in operation and/or when installed, fromthe object is the ascending order in which these surfaces are referredto as the first surface (or surface I), the second surface (or surfaceII), the third surface (or surface III), the fourth surface (or surfaceIV) and other surfaces if present. For example, in the case of anembodiment shown in FIGS. 1A, 1B, the direction of incidence of light isindicated as the z-axis. Generally, therefore, surfaces of thestructural elements (such as substrates) of an embodiment of theinvention are numerically labeled starting with a surface thatcorresponds to the front portion of the lens system and that is proximalto the object and ending with a surface that corresponds to the backportion of an assembly and that is proximal to the retina. Accordingly,the term “behind” refers to a position, in space, following a positionof something else and suggests that one element or thing is at the backof another as viewed from the front of the lens assembly. Similarly, theterm “in front of” refers to a forward place or position, with respectto a particular element as viewed from the front of the assembly.

Examples of Embodiments for Ophthalmic Use.

FIGS. 1A and 1B schematically illustrate, in side view, an anterior lens110 and a posterior lens 114, each equipped with corresponding flexiblehaptic elements 120, 124 structured to interlock the individual lenscomponents (or lenses, lenticles, lenslets) 110, 114 together to form,in operation, an interlocked embodiment of the intraocular lens system.An example of such embodiment is shown as 200 in FIGS. 2A and 2B. Theside structures, or haptics, 120, 124 hold the lens system in placewithin the capsular bag inside the eye (as later discussed in referenceto FIG. 4). (It is appreciated that, generally, more than two—forexample three, four, or more—lenslets in series may be used to form anembodiment of the invention. In an embodiment in which more than twointercoupled lenslets components are used to form an IOL, the operationof the IOL includes a deformation of multiple surfaces that are internalto the IOL. For simplicity of illustration, the structure of the IOLthat includes more than two lenses in series is not shown, as theprinciple of its operation is substantially similar to that describedbelow in reference to the IOL including two lenslets.) In a specificimplementation, the optical portions 126, 128 of lenses 110, 114 (shown,in this embodiment, with beveled peripheral edges 126A, 128A) havemutually-opposing surfaces 132, 136, (or surfaces II and III) eachhaving, in a specific case, a corresponding prolate aspherical shape(although these opposing surfaces can generally be shaped differently).

Each of the lenses 110, 114 are deformable and foldable, and are madefrom silicone and/or acrylic materials commonly used for construction ofIOLs such as, for example, foldable/flexible hydrophobic and/orhydrophilic acrylic, silicone, hydrogel, collamer, and/or rigid PMMAwhen required.

The interlocking haptic element 120 and the stabilizing haptic element124 are shown to include two portions each (the upper portion and thelower portion, as seen in FIGS. 1A, 1B), the corresponding portions ofthe anterior lens haptic 120 and the posterior lens haptic 124 beingpaired in operation. However, a chosen lens may have different number ofhaptic portions—for example, three, or more—and other lens(es) of thesystem will have, in this case, respectively corresponding hapticportions for pairing with the ones of the chosen lens. In oneimplementation the haptics are symmetric about an optical axis 130.Haptics of lenses 120, 124 define monotonically-curved, for exampleoval, outer surfaces (as shown, surfaces 140, 144) in absence ofmechanical stress. As shown in FIG. 3, at least one of the hapticportions 124 of the posterior lens 114 includes a locking notch 150 inthe wing-portion of the haptic and an interlocking haptic channel orgroove 154 dimensioned, in the posterior surface of the lens 114, tofixatedly and securely accommodate the interlocking haptic extensions120 of the anterior lens 110 when the two lenses 110, 114 are beinginterlocked. While the interlocking haptic-accommodating groove 154 isshown to extend, in the surface 144, along an arc to an edge of thehaptic element 124, in an alternative implementation the groove orchannel 154 may be terminated earlier, before the edge of the haptic124.

In practice, the lenses 110, 114 are inserted individually, separately,while folded, through a small incision in the eye (typically, under 3 oreven 2 mm in size) to minimize surgical trauma, unfolded in the volumedefined by the capsular sack such as to ensure that the curved surfaces140, 144 and the outer surfaces I, II conform to the shape of the lenscapsule. The lenses are then coupled together by rotating of one of thelenses with respect to another about the optical axis (axis z as shownin FIGS. 1A, 1B) to pass an interlocking haptic 120 through a notch 150such that the end of the haptic 120 is rested in and along theinterlocking channel 154 of the stabilizing haptic 154. As a result ofsuch interlocking, a portion of a haptic 120 that is proximal to theoptical portion of the lens 110 is located in front of a stabilizinghaptic 124 of the lens 114 and in the notch 150, while a portion of ahaptic 120 that is distal to the optical portion of the lens 110 islocated behind the haptic 124 of the lens 114, in the groove 154. Thehaptics are structured such that, in the interlocked position, thesurfaces II, III (the inner surfaces of the IOL system) are placed incontact at the axial point P (in a specific embodiment—withoutsubstantial deformation of surfaces II, III) to provide full refractivepower of the surfaces II, II for near-distance accommodation of the IOLsystem, while the interlocked haptics exert small redial pressure on thenatural lens capsule along the IOL-system's long axis.

The haptics 120, 124 are designed to be supported in their rigiditywithin the natural lens capsule retained following the cataractextraction (shaped as a lobsided oval in a cross-section, with the longaxis of about 8.2 mm and a short axis of about 4.2 mm, with the anteriorcurvature of approximately 9 mm and posterior curvature of about 6.5 mm)The outer limits of the haptics are flared with rounded edges todistribute stress over a large area of the capsule, which limitsnon-azimuthally symmetric deformation and the risk of capsular rupture.The haptics are structured to conform to the posterior surface of thecapsule out to its equator and, when so conformed, are able to counterthe net anterior vector of force by transmitting the force centripetallyto the equator of the capsule. Lastly, the haptics are designed to havesuch a width as to increase their rigidity and prevent rotationalbuckling.

It is noted that one operational shortcoming of some of existing to-datemechanical structures of accommodating IOLs of the related art is thatthe small force applied by the capsule 116 to the lens is not sufficientto actuate the lens and alter its shape and power. In contradistinctionwith accommodating IOLs of the related art, embodiments of the presentinvention are structured to directly transfer the force, caused byflexing of the ciliary body muscle, to the mutually opposing surfacesII, III of the optical portions of the component lenses 110, 114 such asto alter their shapes, causing substantially no loss of force upontransmission that would otherwise occur if the force were transferred toany other an internal or anterior surface of the optical portion of theembodiment. (For example, in one embodiment, the smallactuating/accommodating force of about 1 gram is sufficient for theoperation of the lens of the present invention.)

FIG. 10 shows diagrammatically the human eye. To this end, and inreference to FIG. 10, FIG. 4 illustrates, in a simplifiedcross-sectional view, an example of operable cooperation with andspatial orientation of the embodiment 200 inside the eye. Each of theindividual lenses 126, 128 can be inserted individually, while foldeddue to the flexibility of the material they are made from, through anapproximately 3 mm incision in the eye (which is a currently usedapproach), to reduce trauma to the eye. Following the insertion, thelenses 126, 128 are interlocked to form the IOL 200.

Upon the formation of the interlocked IOL system, the free ends of theinterlocked haptics 120, 124—which are distal to optical portions of thecorresponding lenses—are placed in the lens capsule (also referred to ascapsule bag) 410 of the now-removed natural lens of the eye to beabutted against the equatorial portion of the capsule 410 (against thecapsule in the peripheral portion of the volume defined by it). The lenscapsule does not adhere to silicone, and therefore the optics is kept inplace by the haptics. When the ciliary body muscle 414 is relaxing (forexample, during the focusing of the eye at a large distance), tension onthe zonules (ciliary zonules) 420 and/or the capsule 410 is increasedcentripetally. As a result, a force 430, vectored outwardly from theaxis 130 and created by tension of zonules 420, increases the radialdiameter of the IOL-system-retaining lens capsule 410, thereby reducingthe pressure exerted by the interlocked haptics 120, 124 onto thecapsule 410 and allowing the previously radially-compressed interlockedhaptics 120, 124 expand radially, which is accompanied by an axialcompression of the lens' optics and decreasing the overall axialthickness D of the system to d<D, as a schematic diagram of FIGS. 5A, 5Billustrate.

The axial compression of the IOL system is additionally bolstered by thecompression of the overlying posterior capsule 410, in which theposterior stabilizing haptics 124 are preventing anterior displacementof the coupled lenses 110, 114. It is worth noting, that in order forsuch “facilitating” compression of the capsule to occur, the capsuledoes not have to be necessarily spatially continuous across the wholeposterior surface of the IOL system (which, in case of the embodiment200 is surface IV). As a result, the lens-system of the presentinvention is operable to achieve the goal of focal accommodation even inthe case when a very common post-cataract surgery procedure (commonlyreferred to as an Nd-YAG laser capsulotomy, which removes a film growththat degrades vision over the central posterior surface of the lenscapsule) has been performed.

Referring again to FIGS. 5A, 5B and in further reference to FIG. 6,showing the enlarged central, axial portion 600 of the lens of FIG. 5Band specifically surfaces II and III in contact, it is understood thatas a result of the combination of the equatorial elongation and theaxial compression of the interlocked lenses 126, 128, surfaces II andIII mutually deforming (deforming each other) such as to define aflattened area 610 across which these surfaces are in continuous contactand are flattened (due to the pliability of the material of theindividual lenses 126, 128) as compared to the shape of these surfacesshown in FIGS. 2B and 5A, when the ciliary muscle is not relaxed. In oneembodiment, such flattened (applanated) area 610 is axially symmetricabout the axis 130. The flattening of surfaces II and III due to themutual deformation of the lenses 126, 128 effectively reduces opticalcontributions of each of these surfaces to the power of the overall lens114 substantially without any direct contribution from axial translation(of an optical component of the overall lens) to the accommodation ofthe IOL 200.

Stated differently, during the contraction of the ciliary muscle, thepulling force applied to the embodiment of the installed IOL radially(or outwardly with respect to the axis of the lens) extends the hapticsoutwardly, which mechanically translates into an axial force that pushesindividual lenses of the IOL axially towards each other therebyincreasing the region of contact between the facing-each-surface of theIOL from the axial point to some measurable area surrounding the axialpoint. As a result, in such region of contact the facing-each-othersurfaces of lenses are applanated, and the overall power of the systemis reduced, resulting in accommodation at large distance (for example,infinity). During the relaxation of the ciliary muscle, on the otherhand, the axial force is reduced and the region of contact between theindividual lenses is reduced, thereby increasing the curvatures of thelens' surfaces within the region of contact and increasing the overallpower of the system, thereby accommodating the IOL accommodation at anear distance. In a specific embodiment, the radii of curvature of thefacing-each-other surfaces II and III are larger than those of the outersurfaces I and IV.

FIGS. 7A, 7B provide diagrams schematically illustrating an opticallayout used for ray-tracing of light through a model of an eye (in whichthe natural lens is substituted with an embodiment of the IOL accordingto the invention) from the object towards the retina to illustrate theability of the embodiment of the invention to refocus within a dynamicrange of distances (from infinity, corresponding to the layout of FIG.7A, to a near-distance which, in the case illustrate in FIG. 7B is about100 mm), which dynamic range substantially exceeds requirements that canbe encountered in practice. Examples of Zemax® model design parameterscorresponding to the layouts of FIGS. 7A, 7B are presented in Tables 1and 2, respectively. The pupil stop was set for 5.1 mm (foraccommodation at infinity) and 3 mm for near-distance accommodation.Surfaces 1, 2 represent the surfaces of the cornea; surface 3 (labelledas “STO”) corresponds to the aperture stop; surfaces 4, 5 correspond tosurfaces I and II of the anterior lens 126, while surfaces 6, 7correspond to surfaces III and IV of the posterior lens 128,respectively. Surface “IMA” corresponds to a surface of the retina.

It is appreciated that the particular example of the IOL design fornear/short distance accommodation was set to a 100 mm distance to object(FIG. 5B) to more clearly illustrate a change of curvatures of themutually-deforming upon variable contact surfaces 5, 6 (II, III) withthe change of accommodation of the IOL from the infinity to a near pointobject. It can be seen that, while for accommodation at infinity (FIG.7A) the surfaces 5, 6 are flattened and in contact across a substantialportion of clear apertures of the lenses 126, 128, for a near-distanceaccommodation the contact area between the surfaces 5, 6 issubstantially reduced to a small region about the optical axis. Inpractice, as would be appreciated by a skilled artisan, the actualphysiological design of the IOL 200 would be optimized for a neardistance to object of about 200 mm or so. All design parameterssummarized in Tables 1, 2 are initial estimates and not necessarilyoptimized and, therefore, corresponding spot diagrams (of FIGS. 8A, 8B)and simulated images (of FIGS. 9A, 9B) do not necessarily reflect thebest quality of imaging achievable with an embodiment of the IOL of theinvention.

TABLE 1 Zemax ® design parameters corresponding to layout of FIG. 7ARadi- Thick- Semi- Surf: Type us ness Glass Diameter Conic OBJ StandardInfinity 1.000E+004 1.733E+004 0.000 1* Standard 7.800 0.550 3775716.000 U −0.600 2* Standard 7.800 2.970 337613 6.000 U −0.100 STO*Standard Infinity 1.500 337613 2.800 U 0.000 4* Standard 11.100 0.700470519 3.000 U 0.000 5* Standard Infinity 0.000 337613 3.000 U −2.000 6*Standard Infinity 0.700 470519 3.000 U −2.000 7* Standard −11.100 16.930336611 3.000 U −2.000 IMA Standard −13.400 — 336611 12.600 U 0.150

TABLE 2 Zemax ® design parameters corresponding to layout of FIG. 7BRadi- Thick- Semi- Surf: Type us ness Glass Diameter Conic OBJ StandardInfinity 100.000 178.337 0.000 1* Standard 7.800 0.550 377571 6.000 U−0.600 2* Standard 7.000 2.970 337613 6.000 U −0.100 STO* StandardInfinity 1.500 337613 2.800 U 0.000 4* Standard 11.100 0.700 4705193.000 U 0.000 5* Standard −22.000 0.000 337613 3.000 U −2.000 6*Standard 22.000 0.700 470519 3.000 U −2.000 7* Standard −11.100 16.930336611 3.000 U −2.000 IMA Standard −13.400 — 336611 12.600 U 0.150

The degree of mutually-caused applanation (of the facing each othersurfaces II, III of the embodiment of FIGS. 5A, 5B the parameters ofwhich are listed in Tables 1 and 2) as a function of force applied tothe lens surfaces is shown in FIG. 12, showing a substantially quadraticresponse of a lens' surface.

In a specific embodiment in which surfaces II and III possess prolateasphericity in the unstressed state (as schematically illustrated inFIGS. 1A, 1B, 2B, 5A), parameters of such asphericity are judiciouslychosen to increase the efficiency of operation of the IOL 200 by takingadvantage of natural miosis, as compared to the case when surfaces IIand III are spherical, for example. Miosis (pupillary constriction)accompanies eye-lens accommodation to a near object. Due to the veryshape of the prolate aspheric, the central portion of the IOL 200located very close to the optical axis 130 has increased optical poweras compared to the outer, peripheral portion of the IOL. When the pupilof the eye is constricted during near-distance accommodation, the clearaperture of the eye corresponds to only the small central portion of theunstressed lens, where the maximum curvature occurs in the prolateasphere, while the contribution of the peripheral portion of the lenshaving lower power contribution than that of the utilized centralportion is not utilized. Conversely, during the long-distanceaccommodation of the eye with the IOL 200, the clear aperture of the eyeis larger (due to papillary dilation accompanying such long-distanceaccommodation), while the mutual flattening of surfaces II and III inthe area 610 of the IOL 200 (which includes both the central, axialportion of the lens and at least some of the peripheral portion of thelens that) reduces the contribution of the area 610 to the overall powerof the lens. Accordingly, the amount of force that the ciliary musclehas to apply to achieve a certain degree of accommodation of aembodiment of the lens two facing each other surfaces of which areprolate aspheric is advantageously smaller that that required to achievethe same degree of accommodation when the surfaces at hand are eitherspherical or, generally, have a shape differing from prolate aspheric.FIG. 9 illustrates a dependence of accommodation power and a degree ofapplanation in an embodiment of IOL 114 as a function of the equatorialforce applied to the haptics of the IOL 200 having optical, geometrical,and material parameters discussed above The data presented in FIG. 9were calculated the formula is based the closest fit curve to a finiteelement analysis model, which follows the general form of “ApplanatingForce=A*Applanated Area)²”; here, the factor A incorporates both themodulus of elasticity of the material of the lens and the curvature ofthe opposing surface. The percent applanated area is substantiallylinearly related to the percent lens power. The assumptions used in suchassessment include: negation of the lens power contributed by the inneropposing surfaces of the IOL over the applanated diameter, and anegligible change in surface curvature of the outer surfaces of the IOL.

In reference to FIG. 11, a flow-chart illustrating an embodiment of themethod for vision correction is presented. The embodiment includesinstalling, in a required order, first and second individual lenses in acapsular membrane of an eye at step 1110. The implantation mayoptionally include folding the IOL, at step 1110A. It is appreciatedthat material composition of IOL embodiments of the invention allows theIOLs to be folded and inserted into the eye through a small incision(which make them a better choice for patients who have a history ofuveitis and/or have diabetic retinopathy requiring vitrectomy withreplacement by silicone oil or are at high risk of retinal detachment).At step 1120, the so inserted individual lenses are unfolded inside theeye such as to place each of the 2D-curved haptics of these lenses inmechanical cooperation with ciliary muscle of the eye.

The unfolding is followed by orienting the lenses in a capsule membraneof the natural lens of the eye such as to position the correspondingprolate aspherical surfaces of the first and second individual lenses toface each other, as step 1124. The posteriorly located individual lensthat has an outer prolate aspheric surface facing the cornea is placedsuch as to be separated from the cornea by the anteriorly placedindividual lens. Each of the first and second individual lenses has aset of haptics structured to be affixed to one another (optionally—via arotational movement about an optical axis of one of the lenses) at step1128 such as to form an IOL in which the individual lenses are in aphysical contact at an axial point of the corresponding prolate asphericsurfaces and in which the haptic extension elements of one individuallens are passing through the locking notches of the receiving haptics ofanother individual lens while portions of these extension elements(including the ends of the extension elements) are rested in theinterlocking grooves of the receiving haptics.

The formed IOL contains (i) a central optical portion that has anoptical axis and that is formed by first and second optical elementsthat have respectively corresponding oblate aspheric surfaces in contactat their axial points and (ii) a set of flexible curved haptics, each ofsaid haptics having proximal and distal sides, the proximal side beingintegrated with the central optical portion along a perimeter thereof.Either the step of unfolding or the step of interlocking may beaccompanies with juxtaposing the flexible haptics and the posteriorsurface of the posteriorly positioned individual lens against aninterior surface of a capsule membrane of a natural lens of the eye suchas to place distal side of each of said haptics in mechanicalcooperation with the capsule membrane.

Embodiment of the method may include step 1130, during which an area ofcontact between prolate aspheric surfaces, of the IOL, that are facingeach other internally to the IOL is changed as a result of transmittinga force, applied to the interlocked haptics, centripetally to theequator of the IOL and transferring at least one of the equatorially andaxially pressure formed by such force. The step of changing the area ofcontact is accompanied by applanation, 1130A, of these surfaces that ismutually-imposed on one another by the immediately adjacent individuallenses of the IOL on as a result of which a change of focal length ofthe IOL is realized. In particular, such change can be effectuated, atstep 1130B, to a higher degree in the axial portion of the prolateaspheric surface than in a peripheral portion of such surface.

For the purposes of this disclosure and the appended claims, the use ofthe term “substantially” as applied to a specified characteristic orquality descriptor means “mostly”, “mainly”, “largely but notnecessarily wholly the same” such as to reasonably denote language ofapproximation and describe the specified characteristic or descriptor sothat its scope would be understood by a person of ordinary skill in theart. The use of this term neither implies nor provides any basis forindefiniteness and for adding a numerical limitation to the specifiedcharacteristic or descriptor. For example, a reference to a vector orline being substantially parallel to a reference line or plane is to beconstrued as such vector or line extending along a direction that is thesame as or very close to that of the reference line or plane (forexample, with angular deviations from the reference direction that areconsidered to be practically typical in the art). As another example,the use of the term “substantially flat” in reference to the specifiedsurface implies that such surface may possess a degree of non-flatnessand/or roughness that is sized and expressed as commonly understood by askilled artizan in the specific situation at hand.

When integrated for operation, the IOL assembly sits within the existinglens capsule following cataract extraction, and is operable bymechanical axial compression and radial elongation created by thezonular tension (just as a natural lens works, with the sameneurological feedback control actuation). Internal, facing each-othersurfaces of the lens assembly mutually deform to change an overalloptical power o the assembly and subsequently accommodate the assemblyby concentrating both the force of existing capsular axial compressionand radial elongation to small internal surface area which deforms tocreate the power change. Two or more interlocked-through-hapticsmutually-deforming deforming lens elements, forming the assembly,effectively combine the total physiologic force available from axialcompression and radial elongation. Lens elements can be inserted to thelens capsule separately and coupled (interlocked) internally.

Disclosed aspects, or portions of these aspects, may be combined in waysnot listed above. Accordingly, the invention is not intended and shouldnot be viewed as being limited to the disclosed embodiment(s), andcertain modifications not changing the scope of the invention can bemade. For example, and in reference to a specific embodiment depicted inFIGS. 1A and 1B, it is not necessary that the individual lens at thefront (lens 126 in FIG. 1A) has haptic extension elements while theposterior individual lens (lens 128 in FIG. 1B) has haptics withresponding locking notches and interlocking grooves: the types ofhaptics can be reversed such that it is the front lens component in theIOL system that has a haptic containing notches and grooves, whileanother individual lens component is equipped with corresponding hapticextension elements. Similarly, while (both) individual lenses on the IOLsystem of the invention have been depicted to lenses of positive opticalpower, the scope of the invention and the principle of operation of theinvention does not change when at least one of the individual lenses ofthe overall IOL system is a lens with negative optical power.

Moreover, the scope of the invention is not limited to any specificshape of the lens. As non-limiting examples, either of biconvex,plano-convex, plano-concave, biconcave, positive meniscus, and negativemeniscus lenses (optionally modified to provide for prolate asphericityof the mutually-deforming surfaces, as discussed above) can be employedto implement an embodiment of the invention. It is also appreciated thata different number of individual lenses (three or more, for example) canbe used to form an interlocked embodiment of the IOL in a fashionsimilar to that disclosed above, the accommodation to a near-distanceobject in such IOL being effectuated at least partly due to theapplanation of the mutually-deforming, facing each other surfaces of theimmediately-adjacent individual lenslets.

Alternatively, a train of optical elements from which the overall IOLsystem is formed may include an optical element possessing asubstantially zero optical power. An example of one specific embodiment1300, in which an element 1310 is positioned co-axially with and betweenthe individual lens components 126, 128 is illustrated in FIG. 13,without the showing of optional corresponding haptic elements, forsimplicity of illustration. In this structure, the optical surfaces arelabeled sequentially, along the z-axis (a direction of propagation oflight from an object), such that the anterior lenslet 126 has surfacesI, II; the element 1310 has surfaces III, IV; and the posterior lens 128has surfaces V, VI. In this implementation, the element 1310 may becharacterized by, for example, slightly negative optical power oroptical power that is substantially zero, and be made from a softmaterial such as silicone or collamer material having a modulus ofelasticity that is at least an order of magnitude smaller than that ofneighboring lenslets (which, in turn, may have different moduli ofelasticity as compared to one another). The moduli of elasticity for thevarious materials may range (but not limited to) between about 1000 kPaand abut 1 kPa. These parameters are chosen to provide for a modulus ofelasticity of the element 1310 that is lower than moduli of elasticityof the lenses 126, 128.

Furthermore, it is recognized that, generally, a given individualcomponent or lenslet of the overall interlocked IOL system may, in aspecific embodiment, have a complex structure such as, for example, oneof those disclosed in U.S. patent application Ser. Nos. 14/193,301 and14/195,345, the disclosure of which is incorporated herein by reference.As a non-limiting example and without loss of generality, an individuallens component of the present embodiment 200 can be structured to havean optical portion configured as gel-based lens discussed in Ser. No.14/195,345 in reference to FIGS. 1A and 1B therein. In this case, anindividual lens components may be structured as a lens having a (i)first rotationally symmetric optical portion with an optical axis and afocal length and defined by a first oblate aspheric surface and adeformable prolate aspheric surface, the optical portion operable togradually change the focal length in response to deformation of theprolate aspheric surface; and (ii) first and second flexible hapticwings, each having proximal and distal sides, the proximal side beingintegrated with the first rotationally symmetric optical portion atleast along a perimeter thereof, such that said lens is dimensioned tobe placed, in operation, in mechanical cooperation with a ciliary bodymuscle of an eye of a subject such that, in response to tension appliedto a at least one of zonules and capsular membrane of a natural lens ofthe eye by the ciliary body muscle, a curvature of the prolate asphericsurface is changed substantially without axial repositioning of saidlens to cause a change in the focal length.

As another non-limiting example, an individual lens component of thepresent embodiment can be structured as a fluidic intraocular lens withflexible interior membrane discussed in Ser. No. 14/195,345 in referenceto FIGS. 9A, 9B therein. In this case, an individual lens component maybe structured as a lens comprising (i) a first rotationally symmetricoptical portion having an optical axis and a first optical power,wherein a first volume of the first rotationally symmetric opticalportion is defined by a posterior curved plate having a first perimeterand a flexible membrane, said first volume being filled with a firstfluid having a first refractive index; (ii) a secondrotationally-symmetric optical portion co-axial with the firstrotationally symmetric portion and having a second optical power,wherein a second volume of said second rotationally symmetric opticalportion is defined by an anterior rigid curved plate having a secondperimeter and said flexible membrane, said second volume being filledwith a second fluid having a second refractive index, such that theposterior and anterior plates being integrated with one another alongsaid first and second perimeters and such that flexible membrane aresealingly affixed to at least one of said posterior and anterior platesat least one of the first and second perimeters such as to preventdispensation of any of the first and second fluids from a respectivelycorresponding volume of the first and second volumes; and (iii) firstand second flexible haptic wings, each having proximal and distal sides,the proximal side being integrated with at least the anterior plate atleast along the first perimeter; said first and second optical portionsbeing operable to gradually change at least one of the first and secondoptical powers in response to deformation of said membrane while theanterior and posterior plates substantially maintain their correspondingshapes.

Examples of Embodiments for Non-Ophthalmic Use.

FIGS. 14A, 14B, 15A, and 15B illustrate schematically in side and frontviews an embodiment 1400 of a variable-focus lens system structured andoperable according to the idea of the invention. Here, the system 1400is shown to include a train (array) of individual lenses 1410, 1420,1430, 1440 disposed sequentially and co-axially about the axis 1450within the housing 1460 that is equipped with an appropriate stopperelement (not shown) at the front portion 1460A of the housing 1460 tokeep the lenses within the hollow of the housing. The individual lensesare made, for example, from materials discussed above in reference toIOL-related embodiments of the invention. As shown, each two immediatelyadjacent lenses are abutting one another at a corresponding axial pointsuch that the mutually-facing surfaces of these two immediately adjacentlenses are in contact with one another at an axial point. For example,surfaces II, III of the system (respectively corresponding to lenses1410, 1420) are in contact at an axial point C, while surfaces VI, VIIof the system (respectively corresponding to lenses 1430, 1440) are incontact at an axial point S. Optionally, at least one of the surfaces ina pair of mutually-contacting surfaces of the lens system 1400 is aprolate aspheric surface. For example, at least one of surfaces II, IIIhas a prolate aspheric profile about the axis 1450.

At the back portion of the housing 1460, an actuating piston 1470 ismated (as known in the art) such as to allow for application of pressureto the train of lenses as a result of movement of the piston 1470 alongthe axis 1450. FIGS. 14A and 14B illustrate the embodiment 1400 when thepiston 1470 is in a neutral position defined by no interactive axialforce between a lens of the system and the surface of the piston. Underthese circumstances, as seen in the front view of FIG. 14B, there issubstantially no applanation of any of the internal surfaces of the lenssystem. In operation (and in reference to FIGS. 15A, 15B), the piston1470 is actuated along the axis 1450—for example, in the directionindicated by an arrow 1474 such at to apply axially-directed pressure toan individual lens of the system 1400. It is appreciated that, dependingon a the piston 1470 can be specifically structured, as will beunderstood by a person of ordinary skill in the art, to apply pressureto either the outermost lens 1440 (thereby creating a force F directedalong 1474 and axially-compressing the combination of lenses 1410, 1420,1430, and 1440), or to another lens in the system. (In one specificimplementation, for example, the piston 1470 can be structured to applypressure to lens 1420, thereby axially compressing the lenses 1410 and1420 such as to applanate the mutually-facing surfaces II, III.) In thegeneral case, however, as shown in FIG. 15A, the piston 1470 compressesthe whole train of lenses of the embodiment 140 o by applying axialforce to the lens 1440. As a result—and as a function of the strength ofthe axially-applied force cause by the movement of the piston 1470—thefacing surfaces of the immediately-adjacent lenses mutually deform eachother, as discussed above in reference to FIGS. 5A, 5B, formingaxially-centered applanated areas 1480. A progression 1480A of suchareas 1480 with radii R_(i) increasing as a function of increasing forceF is schematically shown in FIG. 15B. The applanation 1480 of the lens'surfaces is reversible and repeatable as a result of repositioning ofthe piston 1470 in an opposite direction. To this end, the lens materialworks as a spring reversing the actuation of the lens in proportion toreduction in actuation pressure at the piston 1470.

In one specific implementation, the housing 1460 is a cylindricalconstruction made of a rigid material (for example, metal) while theactuating cylinder of the piston 1470 is made of an optically clearmaterial having a modulus of elasticity of more than 1,000 kPA (such aspoly-methyl-methacrylate, PMMA, for example). The first lens 1410 in theseries of lenses may be also made rigid with a high modulus ofelasticity (such as that of PMMA). The remainder of the internal lenses(as shown, lenses 1420, 1430, and 1440) are constructed of a much softermaterial such as silicone, acrylic, or collamer having a modulus ofelasticity within the range of 0.1 kPa to 100 kPa. The internalapplanating surfaces are compressed between the rigid piston 1470 andrigid lens 1410. The internal opposing lens surfaces are applanatedagainst each other thus progressively negating the optical powercontribution of these surfaces to the overall lens system 1400 as thesurfaces applanate over an increasing diameter, as shown in FIG. 15B.Optionally, the internal immediately adjacent opposing lens surfaces areconstructed in a prolate aspherical manner so that i) to increase thesphericity of such surface as a result of progressive applanation causedby the mechanical compression due to force F, beginning at the apex of agiven surface; and ii) to minimize the discontinuity of spatialtransition between the applanated portion of the surface (centered atthe axis 1450) and the portion of the lens surface encircling suchapplanated area, and associated optical aberrations. The materials,thicknesses, and lens surface curvatures are judiciously chosen suchthat the progressive “stepped” or “staged” applantation of the serialsurfaces approximates a spherical lens over the entire amplitude of lenspower. In other words, at least one of the adjacent opposing lenssurface in question is defined such that, during a process of increasein a diameter of the applanated area in response to increase of force F,optical aberrations of the overall optical system that are caused bychanges in such diameter are minimized.

FIGS. 16A, 16B illustrate a related embodiment 1600 structured to form ahigh-amplitude (from zero to about 20×) zoom lens. Specifically, theoptical train of the system 1600 is formed by an axially concatenatedlens sub-systems 1610, 1620 such that the optical power of one subsystemhas a sign that is opposite to that of the optical power of anothersub-system. As shown in the example of embodiment 1600, the sub-system1610 having an overall positive optical power includes a plurality ofindividual lenses 1612 at least two of which have surfaces contactingeach other at an axial point in absence of axial pressure applied tosuch plurality of lenses. The sub-system 1620, on the other hand, isshown as a group of lenses 1622 possessing, aggregately and as asub-system, negative optical power and separated with a gap 1630 fromthe sub-system 1620. At least two of the lenses 1622 have surfacescontacting each other at an axial point in absence of axial pressureapplied to this group of lenses. In this embodiment, lenses inindividual groups of lenses 1610, 1620 can be actuated such thatactuation of one group of lenses is not connected with or affect theactuation of another group of lenses. For example, as shown, this can beachieved with structuring the means for applying axial pressure to theoptical train of the system 1600 as a combination of two pistons 1670Aand 1670B, operable individually and without interference with oneanother.

Applanting variable-focus lens system structured according toembodiments 1400, 1600 are able to operate within the range ofaccommodation of optical power of about 60 diopters. Negating theoptical power contribution provided by the six internal surfaces of theembodiment 1400 (surfaces II, III, IV, V, VI, and VII) by the stagedapplanation reduces the optical power of the lens system by about 60diopters if each of these internal surfaceds contributes, on average, ofabout 10 diopters of optical power to the overall optical power o thesystem 1400. The lens system requires minimal actuation force of a fewgrams and, in some implementations, about 100 microns of movement tomaximize the range of the optical power. Such actuation may beimplemented with either piezoelectric crystal or a conventional pressureactuator (not shown for simplicity of illustration). FIG. 17 provides aflow-chart of a method of operation of an embodiment of the invention.Here, the operation of the embodiment may be initiated by eithercompressing a group of individual lenses that have been alreadypre-assembled, at step 1710, into an optical train or, alternatively, byforming such assembly at step 1710 to begin with. At step 1720, a motionof an element of the lens-system harness directed along an optical axisof the lens system is transferred to a lens of the system to change areaof contact of mutually-facing surface of the immediately adjacent lensesof the system causing, at step 1730, applanation of an axial portion ofat least one of such surfaces. Optionally, at step 1740, when theso-applanated surface is a prolate aspherical surface, the curvature ofthe axial portion of the prolate aspherical surface can be change morethan the curvature of the peripheral portion of the prolate asphericalsurface (which encircles the axial portion). Other material andmechanical parameters of the system and motion/forces required tooperate such system are similar to those discussed in reference toophthalmological embodiments of the invention.

These and other modifications remain within the scope of the invention.

The invention claimed is:
 1. A pseudophakic lens assembly comprising: afirst lenslet having a first optical power and a firstrotationally-symmetric optical portion that defines a clear aperture ofthe first lenslet, a second lenslet having a second optical power and asecond rotationally-symmetric optical portion that defines a clearaperture of the second lenslet, wherein the first lenslet includes atleast two first haptic portions, each having a proximal. end integratedwith a peripheral region of the first rotationally-symmetric opticalportion and a distal free end; wherein the second lenslet includes atleast two second haptic portions respectively corresponding to the atleast two first haptic portions, each of the at least two second hapticportions including a notch and a groove therein, said groove beingdimensioned to accommodate a corresponding distal free end therein, whenthe first and second lenslets are coaxially positioned to define anaxial point of contact between mutually-facing surfaces-of the first andsecond rotationally-symmetric optical portions thereof, such that eachof the at least two first haptic portions is interlocked with arespectively corresponding second haptic portion, of the at least twosecond haptic portions, through the notch of said corresponding secondhaptic portion as a result of a relative rotation of at least one of thefirst and second lenslets about an optical axis.
 2. A pseudophakic lensassembly according to claim 1, configured to increase an area of contactbetween the mutually-facing surfaces of the first and secondrotationally-symmetric optical portions in response to aradially-vectored force transferred to the first and secondrotationally-symmetric optical portions through the at least two firstand second interlocked haptic portions.
 3. A pseudophakic lens assemblyaccording to claim 1, configured to reduce an area of contact betweenthe mutually-facing surfaces of the first and secondrotationally-symmetric optical portions in response to aradially-vectored force transferred to the first and secondrotationally-symmetric optical portions through the at least two firstand second interlocked haptic portions.
 4. A pseudophakic lens assemblyaccording to claim 1, configured to have a portion of each of themutually-facing surfaces of the first and second rotationally-symmetricoptical portions applanated around an optical axis of the assembly inresponse to a radially-vectored force that is transferred to the firstand second rotationally-symmetric optical portions through the at leasttwo first and second interlocked haptic portions, thereby reducing theoptical power of the assembly.
 5. A pseudophakic lens assembly accordingto claim 1, wherein at least one of the mutually-facing surfaces of thefirst and second rotationally-symmetric optical portions in anunstressed state includes a prolate aspheric surface.
 6. A pseudophakiclens assembly according to claim 1, configured to reduce at least one ofthe first and second optical powers in response to increasing a distancebetween free distal ends of the at least two first haptic portions thathave been interlocked with the respectively corresponding of the atleast two second haptic portions.
 7. A pseudophakic lens assemblyaccording to claim 1, further comprising a third lenslet having; a thirdoptical power and a third rotationally-symmetric optical portiondefining a clear aperture of the third lenslet and at least two thirdhaptic portions, said at least two third haptic portions beinginterlocked with at least one of (i) the at least two first hapticportions and (ii) the at least two second haptic portions to define anaxial point of contact between a first surface of arotationally-symmetric optical portion of the at least one of the firstand second lenslets and a second surface of the thirdrotationally-symmetric optical portion, said first and second surfacesbeing mutually facing, said assembly configured to change an area ofcontact between said first and second surfaces in response to aradially-vectored force transferred to respectively-correspondingrotationally-symmetric optical portions throughrespectively-corresponding interlocked haptic portions.
 8. Apseudophakic lens assembly according to claim 7, configured to have aportion of at least one of said first and second surface surfacesapplanated around an optical axis of the assembly, in response to saidradially-vectored force having been applied to saidrespectively-corresponding interlocked haptic portions.
 9. Apseudophakic lens assembly according to claim 1, configured to have aportion of at least one of the mutually-facing surfaces of the first andsecond rotationally-symmetric optical portions applanated around anoptical axis of the assembly in response to a radially-vectored forcethat is transferred to the first and second rotationally-symmetricoptical portions through the at least two first and second interlockedhaptic portions, thereby reducing the optical power of the assembly.